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Abstract:

A feeding and reversing mechanism for a strapping machine includes a
forward-reverse wheel assembly and a tension wheel assembly which are
mounted on a base and arranged in such a way to provide larger contact
areas between a strapping band and the two wheel assemblies. The feeding
and reversing mechanism further includes first and second spring units.
The first spring unit helps to keep a suitable gap between an active
wheel and a passive wheel of the tension wheel assembly for the strapping
band to pass through. The second spring unit helps to move the passive
wheel toward the active wheel of the tension wheel assembly, so that the
strapping band can be clamped between the passive wheel and the active
wheel tightly to facilitate reversing and tightening of the strapping
band.

Claims:

1. A feeding and reversing mechanism for a strapping machine, comprising:
A base (200) including an installation wall (201) provided with a pivot
(501) thereon; a forward-reverse wheel assembly (30) mounted on the
installation wall (201) and including an active wheel (32) and a passive
wheel (33) adjacent to the active wheel (32) for feeding and reversing a
strapping band (18) passing between the active wheel (32) and the passive
wheel (33); a tension wheel assembly (40) mounted on the installation
wall (201) and including a tension active wheel (41) and a tension
passive wheel (42) adjacent to the tension active wheel (41); a first arm
(50) including spaced first and second ends (51, 54), with the first end
(51) of the first arm (50) mounted around the pivot (501) so that the
first arm (50) is pivotable about an axis defined by the pivot (501),
with the tension passive wheel (40) mounted on the second end (54) of the
first arm (50) so that the tension passive wheel (42) is movable relative
to the tension active wheel (41); a second arm (55) including spaced
first and second ends (551, 553), with the first end (551) of the second
arm (55) mounted around the pivot (501) so that the second arm (55) is
pivotable about the axis defined by the pivot (501), with a rotary member
(56) mounted to the second end (553) of the second arm (55) and being in
contact with a cam (57); a first spring unit (43) including a spring
(432) and a fixing piece (431), with the first spring unit (43) mounted
on the first arm (50) by extending the fixing piece (431) through the
spring (432) and the first arm (50), with the spring (432) biasing the
first arm (50) so that a gap is provided between the tension passive
wheel (42) and the tension active wheel (41) for the strapping band (18)
to pass through; and a second spring unit (45) including a tension spring
(452) and a fastener (451), with the second spring unit (45) installed on
the first and second arms (50, 55) by extending the fastener (451)
through the tension spring (452), the first arm (50), and the second arm
(55), with the second arm (55) being pivoted to move the tension passive
wheel (42) toward the tension active wheel (45) to clamp the strapping
band (18) securely when the cam (57) rotates.

2. The feeding and reversing mechanism according to claim 1, with a band
guiding member (22) disposed on the installation wall (201), with the
tension active wheel (41) disposed below the band guiding member (22) in
a vertical direction, with the tension passive wheel (42) disposed above
the tension active wheel (41) in the vertical direction and adjacent to a
bottom of the band guiding member (22), and with the tension active wheel
(41) disposed between the active wheel (32) of the forward-reverse wheel
assembly (30) and the tension passive wheel (42).

3. The feeding and reversing mechanism according to claim 2, with a
contact surface between the strapping band (18) and the tension active
wheel (41) being larger than half of an outer periphery of the tension
active wheel (41), and with a contact surface between the strapping band
(18) and the active wheel (32) of the forward-reverse wheel assembly (30)
being larger than half of an outer periphery of the active wheel (32).

4. The feeding and reversing mechanism according to claim 2, with the
second end (553) of the second arm (55) being an L-shaped bend relative
to the first end (551) of the second arm (55) and extending in parallel
to the axis of the pivot (501).

5. The feeding and reversing mechanism according to claim 2, with the
passive wheel (33) of the forward-reverse wheel assembly (30) connected
to one end of a swing arm (331) so that the passive wheel (33) is movable
relative to the active wheel (32) of the forward-reverse wheel assembly
(30), and with another end of the swing arm (331) mounted on the
installation wall (201) and engaged with a pressing bar (34).

6. The feeding and reversing mechanism according to claim 2, with the
first arm (50) further including a first engaging ear (52) formed on a
bottom thereof and adjacent to the first end (51) of the first arm (50),
with the first arm (50) further including a second engaging ear (53)
formed on a top thereof and adjacent to the second end (54) of the first
arm (50), with the fixing piece (431) extending through the spring (432),
an installation plate (433) protruded from the installation wall (201),
and the first engaging ear (52) of the first arm (50), with the second
arm (55) further including a connecting ear (552) aligned with the second
engaging ear (53) of the first arm (50) in the vertical direction, and
with the fastener (451) extending through the tension spring (452), the
second engaging ear (53) of the first arm (50), and the connecting ear
(552) of the second arm (55).

Description:

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a feeding and reversing mechanism
for a strapping machine and, more particularly, to a mechanism that can
be used for retracting and tightening a strapping band for strapping
machines.

[0003] 2. Description of the Related Art

[0004] FIG. 10 shows a conventional mechanism 90 for feeding and reversing
a strapping band for a strapping machine which includes a feeding motor
91 and a reversing motor 93. The feeding motor 91 drives a feeding wheel
911 to feed a strapping band 92 from a storage box for strapping objects
or articles. The reversing motor 93 drives a reversing wheel 931 to
retract the strapping band 92 for tightening the objects. Furthermore,
first and second sensors 94 and 95 are provided for counting the rotating
times of the feeding wheel 911 and the reversing wheel 931 respectively
to help measure the length of the strapping band 92 being used, in order
to provide and replenish the strapping band 92 accurately. However, the
mechanism 90 needs two motors, i.e. the feeding motor 91 and the
reversing motor 93, consuming more electricity. In addition, there is
only a point contact between the strapping band 92 and each of the
feeding wheel 911 and the reversing wheel 931, which provide an
inadequate force for clamping the strapping band 92, resulting in
slipping easily during the reversing process of the strapping band 92.
Thus, the conventional feeding and reversing mechanism 90 is ineffective
for strapping the objects.

BRIEF SUMMARY OF THE INVENTION

[0005] Thus, it is an objective of the present invention to overcome the
aforementioned shortcoming and deficiency of the prior art by providing a
feeding and reversing mechanism for a strapping machine. The feeding and
reversing mechanism of the present invention can be used for retracting
and tightening a strapping band and has the advantages of simple
structure. Further, the strapping band can be clamped tightly during the
reversing process without slipping to provide a better strapping result.

[0006] To achieve the foregoing objective, a feeding and reversing
mechanism for a strapping machine of the present invention includes a
base, a forward-reverse wheel assembly, a tension wheel assembly, first
and second arms, and first and second spring units. The base includes an
installation wall provided with a pivot thereon. The forward-reverse
wheel assembly is mounted on the installation wall and includes an active
wheel and a passive wheel adjacent to the active wheel for feeding and
reversing a strapping band passing between the active wheel and the
passive wheel. The tension wheel assembly is mounted on the installation
wall and includes a tension active wheel and a tension passive wheel
adjacent to the tension active wheel. The first arm includes spaced first
and second ends. The first end of the first arm is mounted around the
pivot so that the first arm is pivotable about an axis defined by the
pivot. The tension passive wheel is mounted on the second end of the
first arm and movable relative to the tension active wheel. The second
arm includes spaced first and second ends. The first end of the second
arm is mounted around the pivot so that the second arm is pivotable about
the axis defined by the pivot. A rotary member is mounted to the second
end of the second arm and is in contact with a cam. The first spring unit
includes a spring and a fixing piece and is mounted on the first arm by
extending the fixing piece through the spring and the first arm. The
spring biases the first arm so that a gap is provided between the tension
passive wheel and the tension active wheel for the strapping band to pass
through. The second spring unit includes a tension spring and a fastener
and is installed on the first and second arms by extending the fastener
through the tension spring, the first arm, and the second arm. The second
arm is pivoted to move the tension passive wheel and the first arm when
the cam rotates, so that the tension passive wheel is moved toward the
tension active wheel to clamp the strapping band securely.

[0007] In a preferred form, a band guiding member is disposed on the
installation wall. The tension active wheel is disposed below the band
guiding member in a vertical direction, and the tension passive wheel is
disposed above the tension active wheel in the vertical direction and
adjacent to a bottom of the band guiding member. Further, the tension
active wheel is disposed between the active wheel of the forward-reverse
wheel assembly and the tension passive wheel.

[0008] Preferably, a contact surface between the strapping band and the
tension active wheel is larger than half of an outer periphery of the
tension active wheel, and a contact surface between the strapping band
and the active wheel of the forward-reverse wheel assembly is larger than
half of an outer periphery of the active wheel.

[0009] The present invention will become clearer in light of the following
detailed description of an illustrative embodiment of this invention
described in connection with the drawings.

DESCRIPTION OF THE DRAWINGS

[0010] The illustrative embodiment may best be described by reference to
the accompanying drawings where:

[0011] FIG. 1 shows a diagrammatic, perspective view of a strapping
machine utilizing a feeding and reversing mechanism according to the
preferred teachings of the present invention;

[0012] FIG. 2 shows a perspective view of the feeding and reversing
mechanism of the present invention, with the feeding and reversing
mechanism being a part of a machine center of the strapping machine of
FIG. 1;

[0013]FIG. 3 is a front plan view of the feeding and reversing mechanism
of FIG. 2;

[0014] FIG. 4 is an exploded, perspective view of the feeding and
reversing mechanism of FIG. 2;

[0015]FIG. 5 is a partial, exploded, perspective view of the feeding and
reversing mechanism of FIG. 4;

[0016] FIG. 6 is a view showing an assembled state of a first spring unit
and a first arm of the feeding and reversing mechanism of FIG. 2;

[0017]FIG. 7 is a view showing an assembled state of a second spring unit
and a second arm of the feeding and reversing mechanism of FIG. 2;

[0018] FIG. 8 is a movement illustration of a cam and a rotary member of
the feeding and reversing mechanism of FIG. 7;

[0019]FIG. 9 shows a diagrammatic view of another type of strapping
machine utilizing the feeding and reversing mechanism according to the
preferred teachings of the present invention; and

[0020] FIG. 10 is an illustration of a conventional feeding and reversing
mechanism for a strapping machine.

DETAILED DESCRIPTION OF THE INVENTION

[0021] FIG. 1 shows a door-shaped strapping machine including a frame 10,
a machine center 11, a movable member 15, and two band rails 13 and 131.
The machine center 11 is installed between an upper bar 12 and a lower
bar 121. The upper bar 12 can be moved by transmission of chain wheels
and chains (not shown) so that the machine center 11 is movable upward
and downward with the upper bar 12. The band rails 13 and 131 are
disposed on two vertical sides of the frame 10. Two ends of the lower bar
121 are connected to the band rails 13 and 131 respectively. The movable
member 15 is in the form of a rail and is movably mounted in a chassis
16. During a strapping process, the movable member 15 is driven out from
the chassis 16 and disposed under the band rails 13 and 131, so that the
movable member 15, the lower bar 121, and the band rails 13 and 131
together form a rectangular band rail for transporting a strapping band
18. A band storage mechanism 17 is installed on the chassis 16 for
storing the strapping band 18.

[0022] A feeding and reversing mechanism for a strapping machine according
to the preferred teachings of the present invention is shown of FIGS. 2
through 8 of the drawings and generally designated 3. The feeding and
reversing mechanism 3 of the present invention is a part of the machine
center 11 in FIG. 1, allowing the strapping band 18 to be able to strap
objects tightly. The feeding and reversing mechanism 3 includes a base
200, a forward-reverse wheel assembly 30, a tension wheel assembly 40,
first and second arms 50 and 55, and first and second spring units 43 and
45. The base 200 includes a vertical installation wall 201 and a
horizontal base plate 203. The installation wall 201 is disposed above
the lower bar 121 and provided with a pivot 501. A gear drive assembly 21
is disposed on the installation wall 201 for driving the forward-reverse
wheel assembly 30 and the tension wheel assembly 40. A band guiding
member 22 with a guiding groove is mounted on the installation wall 201
for directing the strapping band 18 to feed or retract. An operation area
24 is disposed below the base plate 203 for fusing and cutting the
strapping band 18 (see FIG. 2).

[0023] The forward-reverse wheel assembly 30 includes an active wheel 32
and a passive wheel 33 (FIG. 4). The active wheel 32 is mounted on the
installation wall 201 and driven by a motor 31. The passive wheel 33 is
connected to one end of a swing arm 331 so that the passive wheel 33 is
movable relative to the active wheel 32. The other end of the swing arm
331 is mounted on the installation wall 201 and engaged with a pressing
bar 34. When the pressing bar 34 is pulled, the swing arm 331 and the
passive wheel 33 are moved together away from the active wheel 32,
allowing the strapping band 18 to be extended through between the active
wheel 32 and the passive wheel 33. Furthermore, a spring 332 is connected
between the swing arm 331 and the installation wall 201. The elasticity
of the spring 332 biases the passive wheel 33 towards the active wheel 32
when the pressing bar 34 is released, so that the passive wheel 33 and
the active wheel 32 can clamp the strapping band 18 for feeding and
reversing the strapping band 18.

[0024] The tension wheel assembly 40 includes a tension active wheel 41
and a tension passive wheel 42. The tension active wheel 41 is mounted on
the installation wall 201 and can be driven by the gear drive assembly 21
to turn. The tension active wheel 41 is disposed below the band guiding
member 22 in a vertical direction. The tension passive wheel 42 is
disposed above the tension active wheel 41 in the vertical direction and
adjacent to a bottom of the band guiding member 22. Moreover, the tension
active wheel 41 is disposed between the active wheel 32 of the
forward-reverse wheel assembly 30 and the tension passive wheel 42. When
the strapping band 18 extends downward from the band guiding member 22,
it will go around the tension active wheel 41 and then the active wheel
32, such that a contact surface between the strapping band 18 and the
tension active wheel 41 is larger than half of an outer periphery of the
tension active wheel 41, and such that a contact surface between the
strapping band 18 and the active wheel 32 is larger than half of an outer
periphery of the active wheel 32 (FIG. 3).

[0025] The first arm 50 includes spaced first and second ends 51 and 54.
The first end 51 is installed around the pivot 501 of the installation
wall 201 (FIG. 5), so that the first arm 50 is pivotable about an axis
defined by the pivot 501. The tension passive wheel 42 is mounted to the
second end 54 of the first arm 50, allowing joint movement of the tension
passive wheel 42 and the first arm 50 relative to the tension active
wheel 41. The first arm 50 includes a first engaging ear 52 formed on a
bottom thereof and adjacent to the first end 51. The first arm 50 further
includes a second engaging ear 53 formed on a top thereof and adjacent to
the second end 54. Furthermore, a sensing piece 421 is disposed on an end
surface of the second end 54 of the first arm 50 for sensing if the
rotating speeds of the tension active wheel 41 and tension passive wheel
42 are the same (It is not a feature of the present invention and
therefore will not be mentioned in details).

[0026] The second arm 55 includes spaced first and second ends 551 and
553. The first end 551 is mounted on the pivot 501 of the installation
wall 201 (FIG. 5), so that the second arm 55 is pivotable about the axis
defined by the pivot 501. The second end 553 is an L-shaped bend relative
to the first end 551 and extends in parallel to the axis of the pivot
501. A rotary member 56 which is a bearing in this embodiment is mounted
on the second end 553 and gets in contact with a cam 57 driven by a motor
571, so that the second arm 55 swings when the cam 57 rotates. The second
arm 55 includes a connecting ear 552 which is aligned with the second
engaging ear 53 of the first arm 50 in the vertical direction.

[0027] The first spring unit 43 includes a spring 432 and a fixing piece
431. The fixing piece 431 extends through the spring 432, an installation
plate 433 protruded from the installation wall 201, and the first
engaging ear 52 of the first arm 50. A nut 434 is coupled to an end of
the fixing piece 431 to install the first spring unit 43 on the first arm
50. The spring 432 can bias the first arm 50 so that a gap is maintained
between the tension passive wheel 42 and the tension active wheel 41 for
the strapping band 18 to pass through.

[0028] The second spring unit 45 includes a tension spring 452 and a
fastener 451. The fastener 451 extends through the tension spring 452, a
washer 453, the second engaging ear 53 of the first arm 50, and the
connecting ear 552 of the second arm 55. A nut 454 is coupled to an end
of the fastener 451 to install the second spring unit 45 on the first and
second arms 50 and 55.

[0029] The procedures for strapping objects using the strapping machine
are mentioned hereinafter. When an object 26 is placed on a conveyor 25
(see FIG. 1) and touches a photoelectric switch on the conveyor 25, the
machine center 11 will descend and stop at a preset position near the
object 26. As the machine center 11 descends, the movable member 15
extends out from the chassis 16 and reaches under the two band rails 13
and 131. Then, the band storage mechanism 17 starts feeding the strapping
band 18. During the feeding process, the strapping band 18 delivered from
the band storage mechanism 17 extends downward from the band guiding
member 22 (see FIGS. 1 through 3), goes around the tension active wheel
41 and the active wheel 32, then passes through the lower bar 121, the
band rail 131, the movable member 15, the band rail 13, and finally
reaches the operation area 24. When the strapping band 18 reaches a
preset location, a photoelectric switch in the machine center 11 will
sense that and activates the motor 31 to turn the forward-reverse wheel
assembly 30 reversely to retract the strapping band 18.

[0030] When the strapping band 18 is retracted to a preset distance from
the object 26, photoelectric switches on the band rails 13 and 131 will
detect that and activate the motor 571 to turn the cam 57, so that the
strapping band 18 is tightened to strap the object 26 tightly. The
strapping band 18 is then fused and cut to finish strapping the object
26.

[0031] The feeding and reversing mechanism 3 of the present invention can
provide better strapping and tightening results for the object 26. More
specifically, the contact surfaces between the strapping band 18 and the
tension active wheel 41 as well as the active wheel 32 are larger than
half of the outer peripheries of the tension active wheel 41 and the
active wheel 32. Therefore, the strapping band 18 can be clamped tightly
without slipping during the reversing process. Moreover, when the
strapping band 18 is being reversed, the motor 571 drives the cam 57 to
rotate intermittently. When the protrusion portion of the cam 57 presses
against the rotary member 56, the second arm 55 swings downward with the
pivot 501 as the fulcrum (FIG. 7); therefore, the second spring unit 45
and the first arm 50 are moved to press the tension passive wheel 42
against the tension active wheel 41 to further clamp the strapping band
18 tightly, enhancing the result of strapping the object 26. Furthermore,
when the strapping process is finished, the elasticity of the spring 431
of the first spring unit 43 returns the first arm 50 and the tension
passive wheel 42 back to their original positions, in order to facilitate
the feeding process of the strapping band 18 for a next strapping
operation.

[0032]FIG. 9 shows a feeding and reversing mechanism 3 of the present
invention being applied in another type of strapping machine 70. The
strapping machine 70 has an arch frame 71 on a top thereof and the object
26 is placed in the arch frame 71. The machine center 11 including the
feeding and reversing mechanism 3 of the present invention is provided in
the strapping machine 70. However, when the feeding and reversing
mechanism 3 of the present invention is applied in this type of strapping
machine 70, the assembling direction of the feeding and reversing
mechanism 3 is opposite to that of the strapping machine shown in FIG. 1,
wherein the pressing bar 34 points downward.

[0033] Thus since the invention disclosed herein may be embodied in other
specific forms without departing from the spirit or general
characteristics thereof, some of which forms have been indicated, the
embodiments described herein are to be considered in all respects
illustrative and not restrictive. The scope of the invention is to be
indicated by the appended claims, rather than by the foregoing
description, and all changes which come within the meaning and range of
equivalency of the claims are intended to be embraced therein.